Is There Such a Thing as Type 3 Diabetes?

The short unconfirmed-by-the-scientific-community answer to the Title of this article is: YES.

According to a paper published this past January in the journal Drugs written by Dr. Suzanne M. de la Monte, Type 3 diabetes is otherwise known as Alzheimer’s disease, the most common cause of dementia in North America. Growing evidence supports the concept that Alzheimer’s is fundamentally a metabolic disease that results in progressive impairment in the brain’s capacity to use blood sugar (i.e. glucose), because the brain cannot respond to insulin and insulin-like growth factor (IGF) stimulation. Insulin is an important hormone that behaves as “the gatekeeper” to get glucose into our cells, including brain cells. Insulin in the brain not only modulates glucose uptake, but also promotes the health of brain cells — their growth, survival, remodeling, and normal functioning.

De la Monte presents a plethora of data that strongly support the notion that there is clearly a similarity between Type 2 diabetes and Alzheimer’s disease (AD) that could not be ignored. The biochemical, molecular, and cellular abnormalities that precede or accompany AD neurodegeneration, are characteristically common, yet they lack a clear origin. Reevaluation of the older literature revealed that impairments in brain metabolism occur early as the symptoms of AD develop. This led de la Monte’s team to develop the concept that impaired insulin signaling has an important role in the pathogenesis of AD. Because this is similar behavior of muscle cells prior the onset of Type 2 diabetes, de la Monte proposed that AD represents “type 3 diabetes.”

Type 1 diabetes mellitus is “juvenile” diabetes that is diagnosed early in life as the pancreas does not produce insulin. Type 2 diabetes, the most common form, is caused by insulin resistance in peripheral tissues, but not the brain necessarily. However, Type 2 diabetics have a 50% chance of developing AD. Individuals with Type 2 have high blood sugar and high blood-insulin because the insulin and glucose are not properly absorbed into the targeted cells.

Therefore, Type 3 diabetes is suggested to have similar physiological symptoms as Type 2 diabetes, however it is only specific to the brain, not necessarily in the rest of the body. A diagnosis of Type 3 diabetes would suggest that the brain alone does not absorb insulin properly. De la Monte’s hypothesis gained more support this past week as another study showed that insulin resistance in the brain precedes and contributes to cognitive decline above and beyond other known causes of AD.

Because we know that lifestyle and dietary choices influence the development of Type 2 diabetes, perhaps the same should be suggested for Alzheimer’s disease. Diabetes is a disease defined as an inability to properly utilize insulin. This would suggest that we should monitor our dietary choices that keep insulin at a low-to-moderate level and participate in regular activities. Talk to your doctor if you have a family history of AD and/or diabetes and what you may be able to do in order to minimize developing either of these.